Sweet-Spot Compression: An Amplification Strategy for Improving Listening Outcomes at Moderate to High Levels.

Only 18 people took part in the first part of the study and 17 in the second, all with mild-to-moderate hearing loss, so the results say nothing about people with more severe loss. Testing was monaural, in a quiet laboratory, at fixed speech and noise levels, with a wearable research hearing aid rather than the participant's own device, so this is not everyday listening. The comparison fitting used an older rule (NAL-NL1). The authors note that current rules (NAL-NL2 and NAL-NL3) prescribe higher compression ratios, which may narrow the gap between the two approaches. Sweet-spot compression sometimes called for gain below zero at high levels, which could not always be delivered with the standard domes used, so the real difference between the two settings was smaller than intended. One participant did much better at 80 dB SPL than at 65 dB SPL, which suggests the linear fitting gave that person too little audibility at the lower level.

Funded by the William Demant Fonden (grant number 21-2011). The authors declare no financial or non-financial conflicts of interest.

Do not conclude that sweet-spot compression stops speech understanding from falling off when speech gets loud. Neither compression setting showed a statistically significant drop between 65 and 80 dB SPL, and the advantage over the comparison fitting came from 17 people with mild-to-moderate hearing loss tested in a laboratory against an older fitting rule.